Summary of performance guarantee and PGTR results
S.No. Minimum process guarantee parameter
Value
PGTR results
1 2 3 4 5
Benzene content in light naphtha product
Max 1.8 wt% Max 34 t/h
0.0 wt%
Flow rate of benzene concentrate (side draw product) Benzene recovery in benzene concentrate (side draw product)
34 t/h
Min 90%
97%
Benzene content in heavy reformate
Max 0.55 vol%
0.2 vol%
Flow rate of heavy reformate
Min 62% of column feed
66%
Table 1
draw product while still meeting the benzene specification for the top and bottom products. Problem statement BPCL aimed to increase benzene recovery at the continuous catalytic regeneration (CCR) unit, which was operating at 125% of design capacity. At this revised charge rate, the existing DWC column was experiencing flooding issues (commonly observed at 105% of column design flow), which lowered separation efficiency and resulted in high benzene content in the heavy reformate and low benzene recovery in the benzene recovery unit. To address these issues, BPCL decided to revamp the existing column for a design flow rate of 115 t/hr. KBR’s approach In 2024, KBR revamped the reformate splitter column again to increase its capacity by 25%. The existing column was revamped to handle a design flow of 115 t/hr feed stream. The revamp was completed with minimal hot work requirements, resulting in an overall shutdown duration of less than three weeks. The existing
tray support rings and dividing wall were utilised, resulting in a reduced turnaround period. DWC design and performance The new DWC was designed to process 115,000 kg/h of feed. This column fractionates the feed into the following three products: Light naphtha: top product. Light reformate: benzene concentrate: side draw. Heavy reformate: bottoms product. The DWC was designed to meet the following product specifications: • Maximum benzene content: 1.8 wt% in light naphtha. • Light reformate flow rate between 20,000 and 34,000 kg/h (maximum 34 t/h). Minimum benzene recovery: 90%. Maximum C5 olefins: 0.16 wt%. • Heavy reformate (bottoms product): Maximum benzene content: 0.55 vol%. Minimum flow rate: 62% of column feed flow. BPCL commissioned the revamped reformate splitter column incorporating modifications
3.00
3.00
2.50
2.50
2.00
2.00
1.50
1.50
1.00
1.00
0.50
0.50
0.00
0.00
108.5 109.0
110.0 110.5 109.5 111.0 111.5 112.0 112.5
103.5
104.0
104.5
105.0
Feed rate ( t/hr )
Feed rate ( t/hr )
Figure 3 Benzene content in heavy reformate during pre-revamp period
Figure 4 Benzene content in heavy reformate during post-revamp period
Refining India
40
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